Sunday, December 22, 2019

Make vacuum pre-loaded spherical air bearings without special tools

A new technique to make graphite air bearings without precision tooling. I show how to make spherical, cylindrical, and flat bearings that are also vacuum pre-loaded, meaning the bearing is captive.

David Preiss' excellent video:

10mm thick graphite sheet:

2" ball bearing:

Small 10-32 hose barb fitting: Linear bearing shaft:

Fusion360 CAD files:

12x18 granite surface plate:

Applied Science on Patreon:

Friday, November 29, 2019

DIY mass spectrometer measures potassium in dietary salt substitute

How to build and operate a simple mass spectrometer. Please ask questions in the comments, as always.

Scientific American article:  $7.99 is a good value for the entire back issue in plain PDF format, and an example of a publisher being reasonable.   I'm happy to support this.

Original Dewdney paper:

Friday, October 11, 2019

Teardown of a "date back" or "data back" camera and description of how it works: A micro LCD projector with incandescent light bulb!

Tuesday, September 3, 2019

Cryogenic treatment of drill bits: tested 2X lifetime and microstructure analysis

I bought some HSS stub drills, and treated half of them with liquid nitrogen, which improved their wear resistance dramatically. I also look at the change in microstructure with an electron microscope.

Performance of cryogenically treated M35 HSS drills -
Performance of cryogenically treated HSS tools -
Effects of Cryogenic Treatment on the Strength
Properties -

LN2 generator video:
Heat treatment of steel video:

Source of drill bits:

Temperature logger (discontinued, unfortunately):

3M fine polishing pads:

Delorean patent on cryogenic torsion bar:

Steel grain structure inspection, and overall great channel for material analysis:

Steel grain structure video:

Applied Science on Patreon:

Monday, August 5, 2019

UV laser creates disappearing ink in normal printer paper

Ordinary printer paper is darkened by a high power UV laser, and then the affected area disappears in four minutes!  This is caused by fluorescent brightening agents that are added to printer paper, which are temporarily overloaded by the intense UV light. It seems that oxygen plays a role in this, as hydrogen peroxide applied to the marks cause them to disappear instantly, and prevent them from being formed again by the laser. Performing the experiment in argon appears to slow the disappearing ink effect.

Wednesday, July 3, 2019

"Bouncy" sulfur hexafluoride gas in tennis balls?

Testing myths about gas inside tennis balls.
Note:  I should have added that all of the gases tested would have the same bounce height in a perfect no-loss system.  The reason that SF6 bounces higher is because it heats less during compression, lowering the amount of possible thermal loss.  Argon heats more during compression, and can lose more energy because of thermal transfer from the gas into the cylinder walls, where it is not restored upon decompression.  Things are more complex in a tennis ball, though:  Most of the losses are in the rubber shell, and not in the thermal dissipation of the fill gas.  It's hard to estimate, but I'd say that the highest fill pressure, with a high-gamma gas would prove to be the most bouncy since it would cause the rubber shell to deform the least.  The amount of compression in a tennis ball is very low, and any effect due to the gamma of the gas will be extremely small.  Fill pressure will have a dramatically bigger effect.

Google drive link :
 Nike Air:

EPA SF6 use:

100 kg load cell:
Instrumentation amplifier:

SF6 on eBay:

Tennis ball patent:

SF6 data sheet:

SF6 worldwide usage:

General adiabatic resources:

Saturday, June 15, 2019

How corrosion inhibitors protect metal: synthesis in the lab and testing

Laboratory synthesis and systematic testing of a corrosion inhibitor commonly found in engine oils.  This inhibitor is the reaction product of 2,5-dimercapto-1,3,4-thiadiazole and oleic acid.

Source of recipe:

Water fogger:

Source of DMTD:

Oleic Acid:

Saturday, June 8, 2019

Photos from Bay Area Maker Faire 2006 onward

2006 - I attended as a spectator, and was completely inspired.  It was the best event of the year for me, and I knew I'd be coming back as an exhibitor.

2007 - I started on my Maker Faire project early in the year, and built an autonomous model helicopter that used ultrasonic beacons to locate and orient itself in space.  This was long before the drone craze, and small flying devices were still pretty new.  Overall, the helicopter didn't fly very well, but I still had an absolute blast.  Most Makers were situated in Fiesta Hall in those early days.

2008 - I teamed up with my friend Peter, and built a set of "interactive furniture" -- furnishings that provided additional features to the owner.  We had a coffee table with a rheoscopic fluid disc, a table with a refrigerator inside, a table with an espresso machine inside, a watering can that could be controlled via web interface, and speaker stands that are also aquariums.

Another friend, also named Peter, brought his electric bikes, and did a great job explaining how different hybrid drive systems worked.

2009 - I helped Peter again with his electric bikes.  There was a lot interest in alternative commute vehicles.  This was long before the scooter craze, etc.

2010 - I built a liquid nitrogen generator from an old cell phone RF filtering device (it used superconductors, and needed cryo to make the filters efficient).  I also brought my rheoscopic coffee table again.

2011 - I built a scanning electron microscope in part because Maker Faire gave me the inspiration and venue to show it off.  Youtube was also a draw, but I think without getting feedback and excitement from the crowds at earlier Faires, I may not have done it.

2012 - I brought a bunch of demos of "liquid lens technology" or electrowetting.  This includes the demo of moving a stream of water with an electrically charged object.  I don't know what happened to my photos.  I also brought the SEM again.  I was interviewed by Mark Frauenfelder this year, I think, and also gave a talk on the SEM.

2013 - Cookie perfection machine!  I built a somewhat silly robot to mix ingredients to make a single cooke -- allowing ingredient proportions to be changed for each one.  Again, photos seem missing.

2014 - I built a ruby laser, and did demos of blasting holes in thin steel objects.

2015 - I decided to built a true DIY project, and developed plans for folks to build their own rheoscopic disk from common parts.  I wrote an article for Make Magazine describing this project.

2016 - I attended as a spectator, which is a very fun way to experience the Faire after having gone as an exhibitor for many years.

2017 - Spectator again.  I'm not sure where my photos went.  At some point in life, I made the effort to be more "in the moment", which meant less snapping photos, and constantly handling a cell phone.

Maker Faire has had a tremendously positive impact on my own development as a creative person, and allowed me to meet like-minded folks that I would never have been able to find otherwise.  We need to make sure this positive impact is continued in other venues, or by helping Maker find a way to continue in another form.  I'm very interested and willing to help.